Window Wavelet Transform Method to Improve the Accuracy Measurement in White Light Interference

White Light Interferometry (WLI) is increasingly being used in precision three-dimensional surface measurement of opto-mechanical parts and nano-meters sized photoelectric devices thanks to its hight precision, non-contact and can expand the viewing area. In this paper, we proposed a window wavelet transform method to process the interference signal to improve the measurement quality of WLI. This method contributes to significantly minimizing interference caused by external Gaussian noise to the interference signal and accurately determining the zero optical path difference (ZOPD) peak position. From there, the three-dimensional profile of the sample surfaces is accurately measured. Simulations results of different measurement samples have demonstrated the capabilities of the proposed method for improving the accuracy measurement of WLI.